GAS VELOCITIES FROM FREE-FALL GAS ATOMIZER

The flow field of a free fall gas atomiser has been measured in three dimensions using hot wire anemometry and a pitot tube for confirmation of axial flow speeds. A finite difference based fluid dynamics packag e has then been used to model the gas flow from the atomiser geometry. Overall a close fit for the velocity magnitudes was obtained for pred ictions parallel to and along the central axis of the atomiser. An exc eption was a broader but lower peak along the central axis. Hot alumin ium droplets of a distribution reproduced from experimental atomisatio n were injected into the gas flow at the confluence of the gas jets al ong the central axis. The modified gas flow pattern is specifically al tered, when compared to the original single phase flow, close to the a xis where the droplets travel. The resulting mass flowrate at the axia l peak flow corresponds to that expected from the law of conservation of momentum. (C) 1996 The Institute of Materials.